我正在阅读 NeHe 的第一本 OpenGL 编程指南,当涉及到编译完成他的第一个教程的结果时,我发现自始至终都存在错误,这让我很为难。这是发生错误的整个源文件(在 Eclipse CDT 中创建,成功链接了 'opengl32' 'glaux' 'glut32' 'glu32'):
#include <windows.h>
#include <gl/gl.h>
#include <gl/glu.h>
#include <gl/glaux.h>
#define GLEW_STATIC
HGLRC hRC = NULL;
HDC hDC = NULL;
HWND hWnd = NULL;
HINSTANCE hInstance;
bool keys[256];
bool active = TRUE;
bool fullscreen = TRUE;
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
GLvoid ResizeGLScene(GLsizei width, GLsizei height)
{
if(height == 0) height = 1;
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f, (GLfloat) width / (GLfloat) height, 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
int InitGL()
{
glShadeModel(GL_SMOOTH);
glClearColor(0, 0, 0, 0);
glClearDepth(1);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
return TRUE;
}
int DrawGLScene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
return TRUE;
}
void KillGLWindow()
{
if(fullscreen)
{
ChangeDisplaySettings(NULL, 0);
ShowCursor(TRUE);
}
if(hRC)
{
if(!wglMakeCurrent(NULL, NULL))
{
MessageBox(NULL, "Release of DC and RC failed.", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);
}
if(!wglDeleteContext(hRC))
{
MessageBox(NULL, "Release rendering context failed.", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);
}
hRC = NULL;
}
if(hDC && !ReleaseDC(hWnd, hDC))
{
MessageBox(NULL, "Release device context failed.", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);
hDC = NULL;
}
if(hWnd && !DestroyWindow(hWnd))
{
MessageBox(NULL, "Could not release hWnd.", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);
hWnd = NULL;
}
if(!UnregisterClass("OpenGL", hInstance))
{
MessageBox(NULL, "Could not unregister class.", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);
hInstance = NULL;
}
}
BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenFlag)
{
GLuint pixelFormat;
WNDCLASS wc;
DWORD dwExStyle;
DWORD dwStyle;
RECT windowRect;
windowRect.left = 0;
windowRect.right = width;
windowRect.top = 0;
windowRect.bottom = height;
fullscreen = fullscreenFlag;
hInstance = GetModuleHandle(NULL);
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = NULL;
wc.lpszMenuName = NULL;
wc.lpszClassName = "OpenGL";
if(!RegisterClass(&wc))
{
MessageBox(NULL, "Failed to register the window class.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
if(fullscreen)
{
DEVMODE dmScreenSettings;
memset(&dmScreenSettings, 0, sizeof(dmScreenSettings));
dmScreenSettings.dmSize = sizeof(dmScreenSettings);
dmScreenSettings.dmPelsWidth = width;
dmScreenSettings.dmPelsHeight = height;
dmScreenSettings.dmBitsPerPel = bits;
dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
if(ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
{
if(MessageBox(NULL, "The requested fullscreen mode is not supported by\nyour video card. Use windowed mode instead?", "OpenGL", MB_YESNO | MB_ICONEXCLAMATION) == IDYES)
{
fullscreen = FALSE;
}
else
{
MessageBox(NULL, "Program will now close.", "ERROR", MB_OK | MB_ICONSTOP);
return FALSE;
}
}
}
if(fullscreen)
{
dwExStyle = WS_EX_APPWINDOW;
dwStyle = WS_POPUP;
ShowCursor(FALSE);
}
else
{
dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
dwStyle = WS_OVERLAPPEDWINDOW;
}
AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);
if(!(hWnd = CreateWindowEx(dwExStyle,
"OpenGL",
title,
WS_CLIPSIBLINGS |
WS_CLIPCHILDREN |
dwStyle,
0,
0,
windowRect.right - windowRect.left,
windowRect.bottom - windowRect.top,
NULL,
NULL,
hInstance,
NULL)))
{
KillGLWindow();
MessageBox(NULL, "Window creation error.", "ERROR", MB_OK | MB_ICONINFORMATION);
return FALSE;
}
static PIXELFORMATDESCRIPTOR pfd =
{
sizeof(PIXELFORMATDESCRIPTOR),
1,
PFD_DRAW_TO_BITMAP |
PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER,
PFD_TYPE_RGBA,
bits,
0, 0, 0, 0, 0, 0,
0,
0,
0,
0, 0, 0, 0,
16,
0,
0,
PFD_MAIN_PLANE,
0,
0, 0, 0
};
if(!(hDC = GetDC(hWnd)))
{
KillGLWindow();
MessageBox(NULL, "Cannot create a GL device context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
if(!(pixelFormat = ChoosePixelFormat(hDC, &pfd)))
{
ChoosePixelFormat(hDC, &pfd);
KillGLWindow();
MessageBox(NULL, "Cannot find a suitable pixel format.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
if(!SetPixelFormat(hDC, pixelFormat, &pfd))
{
KillGLWindow();
MessageBox(NULL, "Cannot set the pixel format.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
if(!(hRC = wglCreateContext(hDC)))
{
KillGLWindow();
MessageBox(NULL, "Cannot create a GL rendering context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
if(!wglMakeCurrent(hDC, hRC))
{
KillGLWindow();
MessageBox(NULL, "Cannot activate the GL rendering context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
ShowWindow(hWnd, SW_SHOW);
SetForegroundWindow(hWnd);
SetFocus(hWnd);
ResizeGLScene(width, height);
if(!InitGL())
{
KillGLWindow();
MessageBox(NULL, "Initialization failed.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
return FALSE;
}
return TRUE;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch(uMsg)
{
case WM_ACTIVATE:
{
if(!HIWORD(wParam))
{
active = TRUE;
}
else
{
active = FALSE;
}
return 0;
}
case WM_SYSCOMMAND:
{
switch(wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
}
break;
}
case WM_CLOSE:
{
PostQuitMessage(0);
return 0;
}
case WM_KEYDOWN:
{
keys[wParam] = TRUE;
return 0;
}
case WM_KEYUP:
{
keys[wParam] = FALSE;
return 0;
}
case WM_SIZE:
{
ResizeGLScene(LOWORD(lParam), HIWORD(lParam));
return 0;
}
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
MSG msg;
BOOL done = FALSE;
if(MessageBox(NULL, "Would you like to run in fullscreen mode?", "Start Fullscreen", MB_YESNO | MB_ICONQUESTION) == IDNO)
{
fullscreen = false;
}
if(!CreateGLWindow("OpenGL", 640, 480, 16, fullscreen))
{
return 0;
}
while(!done)
{
if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
if(msg.message == WM_QUIT)
{
done = TRUE;
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
else
{
if(active)
{
if(keys[VK_ESCAPE])
{
done = TRUE;
}
else
{
DrawGLScene();
SwapBuffers(hDC);
}
}
if(keys[VK_F1])
{
keys[VK_F1] = FALSE;
KillGLWindow();
fullscreen = !fullscreen;
if(!CreateGLWindow("OpenGL", 640, 480, 16, fullscreen))
{
return 0;
}
}
}
}
KillGLWindow();
return msg.wParam;
}
...这是生成的编译(使用 MinGW、opengl、glut、glaux 添加):
03:52:04 **** Incremental Build of configuration Debug for project GL ****
Info: Internal Builder is used for build
g++ -O0 -g3 -Wall -c -fmessage-length=0 -o "src\\Main.o" "..\\src\\Main.cpp"
..\src\Main.cpp: In function 'BOOL CreateGLWindow(char*, int, int, int, bool)':
..\src\Main.cpp:216:2: warning: narrowing conversion of 'bits' from 'int' to 'BYTE {aka unsigned char}' inside { } is ill-formed in C++11 [-Wnarrowing]
};
^
..\src\Main.cpp: In function 'int WinMain(HINSTANCE, HINSTANCE, LPSTR, int)':
..\src\Main.cpp:356:55: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
if(!CreateGLWindow("OpenGL", 640, 480, 16, fullscreen))
^
..\src\Main.cpp:397:58: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
if(!CreateGLWindow("OpenGL", 640, 480, 16, fullscreen))
^
g++ -o GL.exe "src\\Main.o" -lopengl32 -lglaux -lglaux -lglu32 -lfreeglut
src\Main.o: In function `Z14CreateGLWindowPciiib':
C:\Users\Michael\Desktop\LiTHiA\C++\GL\Debug/../src/Main.cpp:227: undefined reference to `_imp__ChoosePixelFormat@8'
C:\Users\Michael\Desktop\LiTHiA\C++\GL\Debug/../src/Main.cpp:230: undefined reference to `_imp__ChoosePixelFormat@8'
C:\Users\Michael\Desktop\LiTHiA\C++\GL\Debug/../src/Main.cpp:238: undefined reference to `_imp__SetPixelFormat@12'
src\Main.o: In function `WinMain@16':
C:\Users\Michael\Desktop\LiTHiA\C++\GL\Debug/../src/Main.cpp:386: undefined reference to `_imp__SwapBuffers@4'
collect2.exe: error: ld returned 1 exit status
03:52:05 Build Finished (took 1s.598ms)
我很抱歉代码太长了。任何帮助/建议?任何赞赏。提前致谢。
最佳答案
针对 gdi32 的链接(即添加 -lgdi32 到链接器命令行)。此库定义函数 ChoosePixelFormat、SetPixelFormat 和 SwapBuffers,它们在链接器错误消息中被报告为 undefined reference 。
关于C++/OpenGL | "undefined reference to ` _imp__ChoosePixelFormat@ 8`"等等,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27753604/
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